This invention relates generally to foldable containers of the type usually formed of corrugated cardboard, and particularly to such containers which are usually in either an erect state or collapsed state. More specifically, the invention relates to foldable containers wherein various ends of bottom panels of the container are permanently hinged together in such a way that they automatically form the container floor when the side and end walls of the container are pulled apart to thereby erect the container.
U.S. Pat. No. 2,348,378 to Goodyear, shows a foldable container having hinged-together bottom panels for automatically forming the container floor when the container is erected. This container has a full sized bottom panel which covers the entire floor with one single smooth surface. Those skilled in the art will realize that such a container cannot open unless the container material is readily flexible so that the large bottom panel can deploy to the erect position. Thus, stiff strong materials can not be used to make containers according to this invention.
U.S. Pat. No. 4,007,869 to Stolkin et al., shows a foldable container having hinged-together bottom panels for automatically forming the container floor when the container is erected. This container does not have a full sized bottom panel as in Goodyear, but instead uses many panels which meet in the middle of the container floor with some minimal overlap. Thus, although this container may be made from stronger material than that of Goodyear, the floor is inherently weak because none of the bottom panels extend fully from one wall to an opposing wall.
U.S. Pat. No. 4,289,268 to Paige, shows a foldable container having hingedly connected bottom panels for automatically forming the container floor when the container is erected. Although this container does have a full sized bottom panel as in Goodyear, the large bottom panel has a long hinge line which virtually extends from one corner of the container to the other, thus weakening the floor. Also there is no mechanism to keep the container fully erect and thus the container has a tendency to collapse when empty.
Each of the above patents strives to provide a collapsible container with a floor which automatically deploys when the container is erected. In each of these patents, the bottom panels may interfere with each other and with the surrounding side and end walls as they deploy. This inherent difficulty is known in the art as bridging.
It is accordingly an object of the present invention to provide an improved automatic bottom container construction for corrugated container blanks.
It is another object of the present invention to provide a corrugated container with an automatic bottom feature which will not tend to collapse upon erecting.
It is a further object of the present invention to provide an automatic bottom container construction for corrugated container blanks which has floor panels extending fully from wall to opposite wall and further including provisions for avoiding bridging of the bottom panels during erecting and collapsing of the container.
It is a still further an object of the present invention to provide a foldable container with inner and outer walls being formed from a single corrugated blank to form a double walled container.
It is therefore an object of the present invention to provide a foldable container formed of relatively stiff corrugated cardboard, having permanently hinged-together bottom panels which automatically form the container floor when the container is unfolded into an erect condition, and wherein the bottom panels fold from a collapsed state to an erect state without impeding the deployment of each other.